Scientific Kite Design

The complete aerodynamics of kites including the motion of lines:

"Collected Researches on the Stability of Kites and Towed Gliders"
By L. W. Bryant, B.Sc., A.R.C.S., F.R.Ae.S.,
W. S. Brown, M.A., and N. E. Sweeting, of the Aerodynamics Division, N.P.L
Reports and Memoranda No. 2303 February, 1942
The NPL is the UK's National Physical Laboratory.

Here we discover that when the motion of the flying line is included in the analysis, the equations become two orders of magnitude more complicated than they are for low speed aircraft. It has to be said, too, that Bryant & Brown's expensive, heavy, wind tunnel-tested kite, based on the Irving biplane kite, required a wind of "at least 35 m.p.h. before (it) could be safely airborne." It crashed "and became a total loss" after 5 minutes of flight. They couldn't afford to carry on with that project.

Well; it just goes to show... keeping it simple also keeps things affordable. As far as kite designing is concerned, a wind tunnel is no substitute for the real world including turbulence.